Machines and methods for automatically loading and sealing a bag that forms part of a chain of bags have been suggested in the past. For example, in U.S. Pat. No. 3,477,196 which issued to Bernard Lerner and which is owned by the assignee of the present application, a machine is disclosed that automatically loads and seals an opened bag forming part of a chain of bags. Typically, the bags are formed from a plastic web or webs and contiguous bags are defined by appropriately positioned heat seals and perforations. The bags normally define an end opening which is formed by serveing one face along a line of perforations. The other face of each bag is connected by perforations to the adjacent, upstream bag.
Mechanisms have also been suggested for automatically severing a loaded bag from the chain. In U.S. Pat. Nos. 3,882,656 and 3,815,318, also owned by the assignee of the present application, a machine is disclosed which includes a pivotally movable clamping/heat sealing structure which rotates a loaded bag away from the chain of bags thereby causing severance of the bag along a line of weakness preferably formed by perforations.
In many commercially available machines, multiple power sources are needed in order to operate the machine. For example, some machines require electrical power for the drive motors and a source of pressurized air for drive actuators that operate various components forming part of the machine. In some machines a blower is used to provide a stream of air for inflating the bag at the loading station so that product or products can be inserted. In other machines, a separate source of pressurized air is used to provide a short pulse of air in order to effect bag inflation.
Many of these machines are large and cumbersome and require significant floor space in order to operate. Still others, which may be smaller in size, are complicated to operate and/or are difficult to load with a supply of bags. Changing the size of bags being used may require extensive readjustment and expensive machine downtime.